FileBackend.php

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<?php
abstract class FileBackend {
    protected $name;

    protected $wikiId;

    protected $readOnly;

    protected $parallelize;

    protected $concurrency;

    protected $lockManager;

    protected $fileJournal;

    const ATTR_HEADERS = 1; // files can be tagged with standard HTTP headers
    const ATTR_METADATA = 2; // files can be stored with metadata key/values
    const ATTR_UNICODE_PATHS = 4; // files can have Unicode paths (not just ASCII)

    public function __construct( array $config ) {
        $this->name = $config['name'];
        $this->wikiId = $config['wikiId']; // e.g. "my_wiki-en_"
        if ( !preg_match( '!^[a-zA-Z0-9-_]{1,255}$!', $this->name ) ) {
            throw new FileBackendException( "Backend name '{$this->name}' is invalid." );
        } elseif ( !is_string( $this->wikiId ) ) {
            throw new FileBackendException( "Backend wiki ID not provided for '{$this->name}'." );
        }
        $this->lockManager = isset( $config['lockManager'] )
            ? $config['lockManager']
            : new NullLockManager( [] );
        $this->fileJournal = isset( $config['fileJournal'] )
            ? $config['fileJournal']
            : FileJournal::factory( [ 'class' => 'NullFileJournal' ], $this->name );
        $this->readOnly = isset( $config['readOnly'] )
            ? (string)$config['readOnly']
            : '';
        $this->parallelize = isset( $config['parallelize'] )
            ? (string)$config['parallelize']
            : 'off';
        $this->concurrency = isset( $config['concurrency'] )
            ? (int)$config['concurrency']
            : 50;
    }

    final public function getName() {
        return $this->name;
    }

    final public function getWikiId() {
        return $this->wikiId;
    }

    final public function isReadOnly() {
        return ( $this->readOnly != '' );
    }

    final public function getReadOnlyReason() {
        return ( $this->readOnly != '' ) ? $this->readOnly : false;
    }

    public function getFeatures() {
        return self::ATTR_UNICODE_PATHS;
    }

    final public function hasFeatures( $bitfield ) {
        return ( $this->getFeatures() & $bitfield ) === $bitfield;
    }

    final public function doOperations( array $ops, array $opts = [] ) {
        if ( empty( $opts['bypassReadOnly'] ) && $this->isReadOnly() ) {
            return Status::newFatal( 'backend-fail-readonly', $this->name, $this->readOnly );
        }
        if ( !count( $ops ) ) {
            return Status::newGood(); // nothing to do
        }

        $ops = $this->resolveFSFileObjects( $ops );
        if ( empty( $opts['force'] ) ) { // sanity
            unset( $opts['nonLocking'] );
        }

        $scope = $this->getScopedPHPBehaviorForOps(); // try to ignore client aborts

        return $this->doOperationsInternal( $ops, $opts );
    }

    abstract protected function doOperationsInternal( array $ops, array $opts );

    final public function doOperation( array $op, array $opts = [] ) {
        return $this->doOperations( [ $op ], $opts );
    }

    final public function create( array $params, array $opts = [] ) {
        return $this->doOperation( [ 'op' => 'create' ] + $params, $opts );
    }

    final public function store( array $params, array $opts = [] ) {
        return $this->doOperation( [ 'op' => 'store' ] + $params, $opts );
    }

    final public function copy( array $params, array $opts = [] ) {
        return $this->doOperation( [ 'op' => 'copy' ] + $params, $opts );
    }

    final public function move( array $params, array $opts = [] ) {
        return $this->doOperation( [ 'op' => 'move' ] + $params, $opts );
    }

    final public function delete( array $params, array $opts = [] ) {
        return $this->doOperation( [ 'op' => 'delete' ] + $params, $opts );
    }

    final public function describe( array $params, array $opts = [] ) {
        return $this->doOperation( [ 'op' => 'describe' ] + $params, $opts );
    }

    final public function doQuickOperations( array $ops, array $opts = [] ) {
        if ( empty( $opts['bypassReadOnly'] ) && $this->isReadOnly() ) {
            return Status::newFatal( 'backend-fail-readonly', $this->name, $this->readOnly );
        }
        if ( !count( $ops ) ) {
            return Status::newGood(); // nothing to do
        }

        $ops = $this->resolveFSFileObjects( $ops );
        foreach ( $ops as &$op ) {
            $op['overwrite'] = true; // avoids RTTs in key/value stores
        }

        $scope = $this->getScopedPHPBehaviorForOps(); // try to ignore client aborts

        return $this->doQuickOperationsInternal( $ops );
    }

    abstract protected function doQuickOperationsInternal( array $ops );

    final public function doQuickOperation( array $op ) {
        return $this->doQuickOperations( [ $op ] );
    }

    final public function quickCreate( array $params ) {
        return $this->doQuickOperation( [ 'op' => 'create' ] + $params );
    }

    final public function quickStore( array $params ) {
        return $this->doQuickOperation( [ 'op' => 'store' ] + $params );
    }

    final public function quickCopy( array $params ) {
        return $this->doQuickOperation( [ 'op' => 'copy' ] + $params );
    }

    final public function quickMove( array $params ) {
        return $this->doQuickOperation( [ 'op' => 'move' ] + $params );
    }

    final public function quickDelete( array $params ) {
        return $this->doQuickOperation( [ 'op' => 'delete' ] + $params );
    }

    final public function quickDescribe( array $params ) {
        return $this->doQuickOperation( [ 'op' => 'describe' ] + $params );
    }

    abstract public function concatenate( array $params );

    final public function prepare( array $params ) {
        if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) {
            return Status::newFatal( 'backend-fail-readonly', $this->name, $this->readOnly );
        }
        $scope = $this->getScopedPHPBehaviorForOps(); // try to ignore client aborts
        return $this->doPrepare( $params );
    }

    abstract protected function doPrepare( array $params );

    final public function secure( array $params ) {
        if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) {
            return Status::newFatal( 'backend-fail-readonly', $this->name, $this->readOnly );
        }
        $scope = $this->getScopedPHPBehaviorForOps(); // try to ignore client aborts
        return $this->doSecure( $params );
    }

    abstract protected function doSecure( array $params );

    final public function publish( array $params ) {
        if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) {
            return Status::newFatal( 'backend-fail-readonly', $this->name, $this->readOnly );
        }
        $scope = $this->getScopedPHPBehaviorForOps(); // try to ignore client aborts
        return $this->doPublish( $params );
    }

    abstract protected function doPublish( array $params );

    final public function clean( array $params ) {
        if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) {
            return Status::newFatal( 'backend-fail-readonly', $this->name, $this->readOnly );
        }
        $scope = $this->getScopedPHPBehaviorForOps(); // try to ignore client aborts
        return $this->doClean( $params );
    }

    abstract protected function doClean( array $params );

    final protected function getScopedPHPBehaviorForOps() {
        if ( PHP_SAPI != 'cli' ) { // http://bugs.php.net/bug.php?id=47540
            $old = ignore_user_abort( true ); // avoid half-finished operations
            return new ScopedCallback( function () use ( $old ) {
                ignore_user_abort( $old );
            } );
        }

        return null;
    }

    abstract public function fileExists( array $params );

    abstract public function getFileTimestamp( array $params );

    final public function getFileContents( array $params ) {
        $contents = $this->getFileContentsMulti(
            [ 'srcs' => [ $params['src'] ] ] + $params );

        return $contents[$params['src']];
    }

    abstract public function getFileContentsMulti( array $params );

    abstract public function getFileXAttributes( array $params );

    abstract public function getFileSize( array $params );

    abstract public function getFileStat( array $params );

    abstract public function getFileSha1Base36( array $params );

    abstract public function getFileProps( array $params );

    abstract public function streamFile( array $params );

    final public function getLocalReference( array $params ) {
        $fsFiles = $this->getLocalReferenceMulti(
            [ 'srcs' => [ $params['src'] ] ] + $params );

        return $fsFiles[$params['src']];
    }

    abstract public function getLocalReferenceMulti( array $params );

    final public function getLocalCopy( array $params ) {
        $tmpFiles = $this->getLocalCopyMulti(
            [ 'srcs' => [ $params['src'] ] ] + $params );

        return $tmpFiles[$params['src']];
    }

    abstract public function getLocalCopyMulti( array $params );

    abstract public function getFileHttpUrl( array $params );

    abstract public function directoryExists( array $params );

    abstract public function getDirectoryList( array $params );

    final public function getTopDirectoryList( array $params ) {
        return $this->getDirectoryList( [ 'topOnly' => true ] + $params );
    }

    abstract public function getFileList( array $params );

    final public function getTopFileList( array $params ) {
        return $this->getFileList( [ 'topOnly' => true ] + $params );
    }

    abstract public function preloadCache( array $paths );

    abstract public function clearCache( array $paths = null );

    abstract public function preloadFileStat( array $params );

    final public function lockFiles( array $paths, $type, $timeout = 0 ) {
        $paths = array_map( 'FileBackend::normalizeStoragePath', $paths );

        return $this->lockManager->lock( $paths, $type, $timeout );
    }

    final public function unlockFiles( array $paths, $type ) {
        $paths = array_map( 'FileBackend::normalizeStoragePath', $paths );

        return $this->lockManager->unlock( $paths, $type );
    }

    final public function getScopedFileLocks( array $paths, $type, Status $status, $timeout = 0 ) {
        if ( $type === 'mixed' ) {
            foreach ( $paths as &$typePaths ) {
                $typePaths = array_map( 'FileBackend::normalizeStoragePath', $typePaths );
            }
        } else {
            $paths = array_map( 'FileBackend::normalizeStoragePath', $paths );
        }

        return ScopedLock::factory( $this->lockManager, $paths, $type, $status, $timeout );
    }

    abstract public function getScopedLocksForOps( array $ops, Status $status );

    final public function getRootStoragePath() {
        return "mwstore://{$this->name}";
    }

    final public function getContainerStoragePath( $container ) {
        return $this->getRootStoragePath() . "/{$container}";
    }

    final public function getJournal() {
        return $this->fileJournal;
    }

    protected function resolveFSFileObjects( array $ops ) {
        foreach ( $ops as &$op ) {
            $src = isset( $op['src'] ) ? $op['src'] : null;
            if ( $src instanceof FSFile ) {
                $op['srcRef'] = $src;
                $op['src'] = $src->getPath();
            }
        }
        unset( $op );

        return $ops;
    }

    final public static function isStoragePath( $path ) {
        return ( strpos( $path, 'mwstore://' ) === 0 );
    }

    final public static function splitStoragePath( $storagePath ) {
        if ( self::isStoragePath( $storagePath ) ) {
            // Remove the "mwstore://" prefix and split the path
            $parts = explode( '/', substr( $storagePath, 10 ), 3 );
            if ( count( $parts ) >= 2 && $parts[0] != '' && $parts[1] != '' ) {
                if ( count( $parts ) == 3 ) {
                    return $parts; // e.g. "backend/container/path"
                } else {
                    return [ $parts[0], $parts[1], '' ]; // e.g. "backend/container"
                }
            }
        }

        return [ null, null, null ];
    }

    final public static function normalizeStoragePath( $storagePath ) {
        list( $backend, $container, $relPath ) = self::splitStoragePath( $storagePath );
        if ( $relPath !== null ) { // must be for this backend
            $relPath = self::normalizeContainerPath( $relPath );
            if ( $relPath !== null ) {
                return ( $relPath != '' )
                    ? "mwstore://{$backend}/{$container}/{$relPath}"
                    : "mwstore://{$backend}/{$container}";
            }
        }

        return null;
    }

    final public static function parentStoragePath( $storagePath ) {
        $storagePath = dirname( $storagePath );
        list( , , $rel ) = self::splitStoragePath( $storagePath );

        return ( $rel === null ) ? null : $storagePath;
    }

    final public static function extensionFromPath( $path, $case = 'lowercase' ) {
        $i = strrpos( $path, '.' );
        $ext = $i ? substr( $path, $i + 1 ) : '';

        if ( $case === 'lowercase' ) {
            $ext = strtolower( $ext );
        } elseif ( $case === 'uppercase' ) {
            $ext = strtoupper( $ext );
        }

        return $ext;
    }

    final public static function isPathTraversalFree( $path ) {
        return ( self::normalizeContainerPath( $path ) !== null );
    }

    final public static function makeContentDisposition( $type, $filename = '' ) {
        $parts = [];

        $type = strtolower( $type );
        if ( !in_array( $type, [ 'inline', 'attachment' ] ) ) {
            throw new FileBackendError( "Invalid Content-Disposition type '$type'." );
        }
        $parts[] = $type;

        if ( strlen( $filename ) ) {
            $parts[] = "filename*=UTF-8''" . rawurlencode( basename( $filename ) );
        }

        return implode( ';', $parts );
    }

    final protected static function normalizeContainerPath( $path ) {
        // Normalize directory separators
        $path = strtr( $path, '\\', '/' );
        // Collapse any consecutive directory separators
        $path = preg_replace( '![/]{2,}!', '/', $path );
        // Remove any leading directory separator
        $path = ltrim( $path, '/' );
        // Use the same traversal protection as Title::secureAndSplit()
        if ( strpos( $path, '.' ) !== false ) {
            if (
                $path === '.' ||
                $path === '..' ||
                strpos( $path, './' ) === 0 ||
                strpos( $path, '../' ) === 0 ||
                strpos( $path, '/./' ) !== false ||
                strpos( $path, '/../' ) !== false
            ) {
                return null;
            }
        }

        return $path;
    }
}

class FileBackendException extends Exception {
}

class FileBackendError extends FileBackendException {
}